svn commit: r184924 - in stable/7/sys: . compat/linux modules/cxgb
Konstantin Belousov
kib at FreeBSD.org
Thu Nov 13 07:00:41 PST 2008
Author: kib
Date: Thu Nov 13 15:00:40 2008
New Revision: 184924
URL: http://svn.freebsd.org/changeset/base/184924
Log:
MFC r184501:
The code in linux_proc_exit() contains a race when multiple linux based
processes exits at the same time. The linux_emuldata structure is freed
but p->p_emuldata is left as a dangling pointer to the just freed
memory.
The check for W_EXIT in the loop scanning the child processes isn't safe
since the state of the child process can change right afterwards. Lock
the process and check the W_EXIT before delivering signal.
Approved by: re (kensmith)
Modified:
stable/7/sys/ (props changed)
stable/7/sys/compat/linux/linux_emul.c
stable/7/sys/modules/cxgb/ (props changed)
Modified: stable/7/sys/compat/linux/linux_emul.c
==============================================================================
--- stable/7/sys/compat/linux/linux_emul.c Thu Nov 13 15:00:34 2008 (r184923)
+++ stable/7/sys/compat/linux/linux_emul.c Thu Nov 13 15:00:40 2008 (r184924)
@@ -232,11 +232,11 @@ linux_proc_exit(void *arg __unused, stru
continue;
em = em_find(q, EMUL_DOLOCK);
KASSERT(em != NULL, ("linux_reparent: emuldata not found: %i\n", q->p_pid));
- if (em->pdeath_signal != 0) {
- PROC_LOCK(q);
+ PROC_LOCK(q);
+ if ((q->p_flag & P_WEXIT) == 0 && em->pdeath_signal != 0) {
psignal(q, em->pdeath_signal);
- PROC_UNLOCK(q);
}
+ PROC_UNLOCK(q);
EMUL_UNLOCK(&emul_lock);
}
sx_xunlock(&proctree_lock);
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